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Objective: Susac syndrome (SuS), multiple sclerosis (MS), and primary angiitis of the central nervous system (PACNS) present diagnostic challenges due to overlapping clinical features. We aimed to enhance diagnostic precision by developing the SPAMS (SuS, PACNS, MS) score, a practical radiological tool., Methods: This multicenter study included 99 patients (43 SuS, 37 MS, 19 PACNS) from South American countries. Relevant MRI features were identified through an elastic-net model determined key variables., Results: The SPAMS score assigned 2 points for snowball lesions, 1 point for spokes-like lesions, or if there are more than 4 lesions in the corpus callosum, corpus callosum involvement, or cerebellar involvement. It subtracted 1 point if gadolinium-enhancing lesions or 4 points if Dawson's fingers are present. Bootstrapping validated the optimal cutoff at 2 points, exhibiting a diagnostic performance of area under the curve = 0.931, sensitivity = 88%, specificity = 89%, positive predictive value = 88%, negative predictive value = 89%, and accuracy = 88%., Interpretation: When specific MRI findings coexisted, the SPAMS score differentiated SuS from MS and PACNS. Access to MRI and standard protocol sequences makes it a valuable tool for timely diagnosis and treatment, potentially preventing disability progression and severe clinical outcomes. ANN NEUROL 2024;96:846-854., (© 2024 American Neurological Association.)

Introduction: Mutations in presenilin-1 (PSEN1) account for the majority of cases of familial autosomal dominant early-onset Alzheimer's disease (AD) as well as in sporadic forms. Atypical presentations are reported including extrapyramidal signs. In the last years, a pleiotropic effect of some PSEN1 variants has been reported in Parkinson's disease (PD)., Objective: to report a new PSEN1 mutation characterized by early-onset Parkinsonism (EOPD) without dementia or classical AD biomarkers phenotype., Patient and Methods: An Argentinian 46 years old woman was diagnosed with EOPD at 35 years old with no family history of neurodegenerative disorders. Her medical history included iron deficiency and anemia since childhood. A brain MRI showed moderate frontal atrophy. 18 FDG-PET and PiB-PET as well as CSF biomarkers were inconclusive for AD. Two neuropsychological examinations were compatible with a mild non amnestic cognitive impairment. Whole blood DNA was extracted and whole exome sequencing and analysis was performed., Results and Conclusion: A heterozygous novel missense PSEN1 mutation (position 14:73637540, A > T, pArg41Ser) was identified as a likely causative mutation in this patient. To the best of our knowledge, this case is the first PSEN1 mutation with a l-dopa responsive Parkinsonism lacking distinctive classical AD biomarkers. This case opens a new window to explore the pathophysiological link among PSEN1 and EOPDs and contributes to increase the phenotypes of PSEN1 variants., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Movement disorders are frequent features of prionopathies. However, their prevalence and onset remain poorly described., Methods: We performed a systematic review of case reports and case series of pathologically- and genetically confirmed prionopathies. Timing of symptom and movement disorder onset were documented. Continuous variables were compared between two groups using the Wilcoxon rank sum test and between multiple groups using Kruskal-Wallis test. Categorical variables were compared using Fisher's exact test., Results: A total of 324 cases were included in this analysis. Movement disorders were a common feature at the onset of symptoms in most prionopathies. Gait ataxia was present in more than half of cases in all types of prionopathies. The prevalence of limb ataxia (20%) and myoclonus (24%) was lower in Gerstmann-Sträussler-Scheinker disease compared to other prionopathies (p ≤ 0.004). Myoclonus was common but often a later feature in sporadic Creutzfeldt-Jakob disease (2 months before death). Chorea was uncommon but disproportionately prevalent in variant Creutzfeldt-Jakob disease (30% of cases; p < 0.001). In genetic Creutzfeldt-Jakob disease, E200K PRNP carriers exhibited gait and limb ataxia more often when compared to other mutation carriers., Discussion: Movement disorders are differentially present in the course of the various prionopathies. The movement phenomenology and appearance are associated with the type of prion disease and the PRNP genotype and likely reflect the underlying pattern of neurodegeneration. Reliance on myoclonus as a diagnostic feature of sporadic Creutzfeldt-Jakob disease may delay its recognition given its relatively late appearance in the disease course., Competing Interests: Funding: None. Conflicts of Interest: The authors report no conflicts of interest. Ethics Statement: Not applicable for this category of article., (© 2019 Rodriguez-Porcel et al.)

In the last years, lysosomal storage diseases appear as a bridge of knowledge between rare genetic inborn metabolic disorders and neurodegenerative diseases such as Parkinson's disease (PD) or frontotemporal dementia. Epidemiological studies helped promote research in the field that continues to improve our understanding of the link between mutations in the glucocerebrosidase (GBA) gene and PD. We conducted a review of this link, highlighting the association in GBA mutation carriers and in Gaucher disease type 1 patients (GD type 1). A comprehensive review of the literature from January 2008 to December 2018 was undertaken. Relevance findings include: (1) There is a bidirectional interaction between GBA and α- synuclein in protein homeostasis regulatory pathways involving the clearance of aggregated proteins. (2) The link between GBA deficiency and PD appears not to be restricted to α⁻synuclein aggregates but also involves Parkin and PINK1 mutations. (3) Other factors help explain this association, including early and later endosomes and the lysosomal-associated membrane protein 2A (LAMP-2A) involved in the chaperone-mediated autophagy (CMA). (4) The best knowledge allows researchers to explore new therapeutic pathways alongside substrate reduction or enzyme replacement therapies., Competing Interests: Emilia M. Gatto received honoraria as speaker by Sanofi-Genzyme. Sanofi-Genzyme had no role in the design, execution, interpretation, or writing of the study. Gustavo Da Prat had no conflict of interest. Martin Cesarini received honoraria as speaker by Sanofi-Genzyme. Sanofi-Genzyme had no role in the design, execution, interpretation, or writing of the study. Jose Luis Etcheverry received honoraria as speaker by Sanofi-Genzyme. Sanofi-Genzyme had no role in the design, execution, interpretation, or writing of the study. Guillermo Drelichman received honoraria as speaker and external advisor by Sanofi-Genzyme. Sanofi-Genzyme had no role in the design, execution, interpretation, or writing of the study.

Background: Holmes tremor is a rare symptomatic movement disorder, characterized by a combination of resting, postural, and intention tremor. It is usually caused by lesions in the brainstem, thalamus, and cerebellum. Despite pharmacological advances, its treatment remains a challenge; many medications have been used with various degrees of effectiveness. Stereotactic thalamotomy and deep brain stimulation in the ventralis intermedius nucleus have been effective surgical procedures in cases refractory to medical treatment., Case Report: Here we report a young woman with topiramate-responsive Holmes tremor secondary to a brainstem cavernoma., Discussion: Herein we report a Holmes tremor responsive to Topiramate., Competing Interests: Funding: None. Conflicts of Interest: The authors report no conflict of interest. Ethics Statement: All patients that appear on video have provided written informed consent; authorization for the videotaping and for publication of the videotape was provided.

There are many rare movement disorders, and new ones are described every year. Because they are not well recognized, they often go undiagnosed for long periods of time. However, early diagnosis is becoming increasingly important. Rapid advances in our understanding of the biological mechanisms responsible for many rare disorders have enabled the development of specific treatments for some of them. Well-known historical examples include Wilson disease and dopa-responsive dystonia, for which specific and highly effective treatments have life-altering effects. In recent years, similarly specific and effective treatments have been developed for more than 30 rare inherited movement disorders. These treatments include specific medications, dietary changes, avoidance or management of certain triggers, enzyme replacement therapy, and others. This list of treatable rare movement disorders is likely to grow during the next few years because a number of additional promising treatments are actively being developed or evaluated in clinical trials. © 2017 International Parkinson and Movement Disorder Society., (© 2017 International Parkinson and Movement Disorder Society.)

Background: Hemichorea-hemiballism is a syndrome secondary to different etiologies. Drug-induced hemichorea is a rare syndrome related to selective serotonin reuptake inhibitors. To the best of our knowledge, no previous cases of hemichorea associated with sertraline have been reported., Case Report: A 65-year-old female noticed hemichorea 1 week after initiation of sertraline. After extensive investigations, other causes of hemichorea were excluded. Hemichorea remitted after sertraline withdrawal., Discussion: In our patient, temporal association and the negative clinical assessment supported a diagnosis of likely drug-induced involuntary movement. We hypothesized that enhanced serotonergic transmission in the ventral tegmental area or nigrostriatum may be involved in sertraline-induced hemichorea., Competing Interests: Funding: None. Conflicts of Interest: The authors report no conflict of interest. Ethics Statement: All patients that appear on video have provided written informed consent; authorization for the videotaping and for publication of the videotape was provided.

Frontotemporal lobar degeneration is a neuropathological disorder that causes a variety of clinical syndromes including frontotemporal dementia (FTD), progressive supranuclear palsy, and corticobasal syndrome (CBS). FTD associated with parkinsonism occurs frequently as a result of mutations in the C9orf72 gene and also in the genes coding for the protein associated with microtubule tau (MAPT) and progranulin (GRN) on chromosome 17 (FTDP-17). Herein, we report an Argentinean family, of Basque ancestry, with an extensive family history of behavioral variant of FTD. Twenty-one members over 6 generations composed the pedigree. An extensive neurologic and neurocognitive examination was performed on 2 symptomatic individuals and 3 nonsymptomatic individuals. Two different phenotypes were identified among affected members, CBS in the proband and FTD in his brother. DNA was extracted from blood for these 5 individuals and whole-exome sequencing was performed on 3 of them followed by Sanger sequencing of candidate genes on the other 2. In both affected individuals, a missense mutation (p.P301L; rs63751273) in exon 10 of the MAPT gene (chr17q21.3) was identified. Among MAPT mutations, p.P301L is the most frequently associated to different phenotypes: (1) aggressive, symmetrical, and early-onset Parkinsonism; (2) late parkinsonism associated with FTD; and (3) progressive supranuclear palsy but only exceptionally it is reported associated to CBS. This is the first report of the occurrence of the p.P301L-MAPT mutation in South America and supports the marked phenotypic heterogeneity among members of the same family as previously reported., (Published by Elsevier Inc.)

Background: Dystonic postures possess a great number of differential diagnoses., Phenomenology Shown: We describe a pseudodystonic posture in a 61-year-old woman with skeletal and extra-skeletal abnormalities., Educational Value: Klippel-Feil syndrome represents an unusual cause of pseudodystonic posture to be considered in the differential diagnosis of dystonia.